package checker

import (
	"context"
	"fmt"
	"strings"

	sdk "git.happydns.org/checker-sdk-go/checker"
)

// Rule returns the single aggregated STUN/TURN check rule.
func Rule() sdk.CheckRule {
	return &stunTurnRule{}
}

type stunTurnRule struct{}

func (r *stunTurnRule) Name() string { return "stun_turn" }
func (r *stunTurnRule) Description() string {
	return "Validates STUN binding and TURN allocation against the configured server(s)."
}

func (r *stunTurnRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, opts sdk.CheckerOptions) []sdk.CheckState {
	var data StunTurnData
	if err := obs.Get(ctx, ObservationKeyStunTurn, &data); err != nil {
		return []sdk.CheckState{{
			Status:  sdk.StatusError,
			Message: fmt.Sprintf("failed to get STUN/TURN observation: %v", err),
			Code:    "stun_turn_obs_error",
		}}
	}

	if data.GlobalError != "" {
		return []sdk.CheckState{{
			Status:  sdk.StatusError,
			Message: data.GlobalError,
			Code:    "stun_turn_discovery_error",
		}}
	}
	if len(data.Endpoints) == 0 {
		return []sdk.CheckState{{
			Status:  sdk.StatusError,
			Message: "no endpoints to probe",
			Code:    "stun_turn_no_endpoints",
		}}
	}

	worst := SubTestOK
	var firstFailLine string
	for _, ep := range data.Endpoints {
		w := ep.Worst()
		if statusRank(w) > statusRank(worst) {
			worst = w
		}
		if firstFailLine == "" {
			if f := ep.FirstFailure(); f != nil {
				parts := []string{
					fmt.Sprintf("[%s] %s", ep.Endpoint.URI, f.Name),
				}
				if f.Detail != "" {
					parts = append(parts, f.Detail)
				}
				if f.Error != "" {
					parts = append(parts, f.Error)
				}
				firstFailLine = strings.Join(parts, ": ")
				if f.Fix != "" {
					firstFailLine += ". Fix: " + f.Fix
				}
			}
		}
	}

	state := sdk.CheckState{
		Status: toSDKStatus(worst),
		Code:   fmt.Sprintf("stun_turn_%s", worst),
		Meta: map[string]any{
			"endpoint_count": len(data.Endpoints),
		},
	}
	if firstFailLine != "" {
		state.Message = firstFailLine
	} else {
		state.Message = fmt.Sprintf("All %d endpoint(s) healthy", len(data.Endpoints))
	}
	return []sdk.CheckState{state}
}